1. Field
The present disclosure generally relates to composite parts made by resin infusion of fiber preforms, and deals more particularly with a method and apparatus for infusing a fiber preform with at least two dissimilar resins.
2. Background
Conventional resin infused parts are generally produced by infusing a dry fiber preform with a either a liquid resin or a solid resin whose viscosity will drop significantly once heated. In all cases, the movement of the resin is from one side of the preform to the other. The resulting part has a substantially even distribution of a single resin and exhibits consistent physical properties and appearance throughout. In some applications though, it may be necessary to provide the part with two different resin systems for appearance or for a functional purpose such as anti-abrasion, anti-reflection or impact resistance, to name only a few.
In some applications, the desired surface treatment may be achieved by placing a separate, nonstructural coating in a resin infusion tool before the preform is resin infused. This is typically known as a gel coat and is standard practice in the art of resin infusion. But in more traditional applications, a coating may be applied to the surface of the part after the part has been fabricated. In either event, the surface treatment requires a separate processing step which may be time-consuming and/or labor intensive. Known surface treatments, regardless of the techniques used, generally result in a surface layer that is separate and distinct from the underlying resin part. Besides being generally different in chemistries from the substrate, the surface layer may increase the tendency to delaminate, chip or separate from the laminate, and could result in environmental degradation that may have an undesirable effect on part performance over time.
Accordingly, there is a need for a method and apparatus for producing a monolithic, resin infused parts having an integral surface layer that is similar to and compatible with the base resin system. There is also a need for a method and apparatus of the type described above that permits fabrication of resin infused parts with blended regions of at least two differing resins.